A planned 10.6km cable car route would connect Son Doong Cave with other caves in the area as part of a planned “tourism, service and resort complex”.
Photograph: Carsten Peter/NG/Getty Images

Plans for a cable car in Vietnam’s Unesco-listed Phong Nha-Ke Bang national park would open up the world’s largest cave to mass tourism. But Vietnamese are protesting the project, and experts warn the environmental impact could be devastating.

Quang Binh province announced in October that resort developer Sun Group would build a $212m (£135m) cable car system through the national park, which occupies a remote, mountainous swathe of central Vietnam. The 10.6km route would connect Son Doong Cave, so large it could house an entire 40-story building, with other caves in the area as part of a planned “tourism, service and resort complex”.

According to local official Nguyen Huu Hoai, the cable car would carry 1,000 visitors per hour.

After the announcement drew an unprecedented flood of opposition, the national tourism ministry made clear that it had not yet approved the project. Experts from overseas slammed the plan in local newspaper and TV reports, while Vietnamese activist Bao Nguyen launched an online petition that drew thousands of signatures. However, the tourism ministry then gave the go-ahead for a preliminary survey – a tentative nod of consent.

Sun Group claims the cable car would be the most environmentally friendly means of opening the area to tourism. Company spokesperson Quach Bao Tran also said the project would “develop Quang Binh as a tourism center” and bring “thousands of jobs for the poor local people”. But experts refute these claims.

“The environmental impact would be devastating,” said Andy McKenzie, one of the first explorers to visit the cave.

Researchers fear that building the towers needed to support the cable car could damage the fragile network of caves in the area. Construction on top of Son Doong would put pressure on the already weak ceiling, potentially triggering collapse, according to geomorphologist Vu Le Phuong, who has been studying the cave since the first expedition in 2009.

He also warned that remote Quang Binh province was ill-equipped to handle the millions of tourists that flood popular destinations like Halong Bay.

“The cable car will bring mass tourism to the area – that’s the biggest thing we fear,” Phuong said.

A plant-covered cavescape at Son Doong. Photograph: Carsten Peter/NG/Getty Images

Vietnam is eagerly welcoming resort developers to build enormous tourism and casino complexes in scenic areas, from Dong Van plateau in the north to Phu Quoc Island in the south. Yet Halong Bay’s struggles with overcrowding and pollution demonstrate what happens when desire for development precedes environmental concerns.

Sun Group has already built cable car systems at nearby Ba Na Hills as well as Fansipan, Vietnam’s tallest mountain, in the far north. In September, the developer got approval to build another cable car in Halong Bay.

Unlike these previous projects, the Son Doong cable car faces organised opposition. On the “Save Son Doong” Facebook page, thousands of people expressed their disapproval and even voiced calls for protests.

“In Vietnam, people are personally against many things. But this is the first time they came together to protect a place in an organised way,” said Bien Thuy Nguyen, the former tour operator who started the page.

While Nguyen discourages protest demonstrations, he makes clear that the movement is not just about environmentalism. Inspired by their peers in Hong Kong, young people are demanding a say in their country’s future.

“When they built such things in the past, no one did a thing,” Phuong said. “But young people see what’s happening in Hong Kong. They want to make the country better.”